DotNet RabbitMQClient: Unmarked long running tasks interfere with PortableThreadPool heuristics

[dharshana jagoda]

Hi,

The RabbitMQClient library uses long running tasks without marking them as "long running".

Is it possible to get them changed?

For example is it possible to change

_mainLoopTask = Task.Run(MainLoop);

in https://github.com/rabbitmq/rabbitmq-dotnet-client/blob/main/projects/RabbitMQ.Client/client/impl/Connection.cs#L82

to

_mainLoopTask = Task.Factory.StartNew(MainLoop, TaskCreationOptions.LongRunning);

As you might know, the CoreCLR in Linux uses the PortableThreadPool to dispatch data received via asynchronous IO compared to IOCP threads on Windows. Having unmarked long running tasks interferes with the heuristics used by the PortableThreadPool and delays the expansion of the thread pool due to late detection of low throughput. Practical impact of this is the regular health probe failures of services running Kestrel.

Many thanks,

Dharshana.

[Luke Bakken]

Hello,

Thanks for the information. I have filed the following request - https://github.com/rabbitmq/rabbitmq-dotnet-client/issues/1318

Please note that you can feel free to open issues and submit pull requests to fix them.

Thanks,

Luke

[Luke Bakken]

This discussion is relevant - https://github.com/rabbitmq/rabbitmq-dotnet-client/issues/959

[dharshana jagoda]

Hey Luke,

Thanks for filing the request. Happy to submit a pull request. Do I raise it against the Main branch or 6.x?

Thanks,

Dharshana.

[Luke Bakken]

Hi  Dharshana,

You can open it against 6.x. I feel like the code used to have  TaskCreationOptions.LongRunning and it was removed at some point, but I can't find it in the project history. That long discussion to which I linked may have some clues.